Field of the Invention
The present invention relates to construction of mitochondrial UQCRB mutant expressing cells and utilization of the cells for UQCRB assay system thereof.
Description of the Prior Art
The electron transport chain (ETC) of mitochondria consists of five complexes and plays a crucial rule in energy production by ATP synthesis [1]. There have been numerous studies associated with the roles of various mitochondrial proteins in multiple diseases such as metabolic diseases and cancers [1,2,3,4]. However, information about the relationship between complex III and angiogenesis is limited.
Ubiquinol-cytochrome c reductase binding protein (UQCRB), which is a nuclear-encoded 13.4-kDa subunit of complex III, has been shown to function in association with the electron transport and the maintenance of complex III [5]. Recently, the potential role of UQCRB in angiogenesis has been demonstrated by identifying it as a target of the natural anti-angiogenesis inhibitor terpestacin [6]. UQCRB is involved in mitochondrial reactive oxygen species (mROS)- and hypoxia-inducible factor (HIF)-mediated angiogenesis by modulating the oxygen-sensing mechanism that regulates hypoxia responses. Moreover, UQCRB regulates vascular endothelial growth factor receptor 2 (VEGFR2)-signaling-induced angiogenesis [7]. Recent studies have demonstrated that the genetic variations of UQCRB were observed in several cancers, including hepatocellular carcinoma [8], ovarian cancer [9], pancreatic ductal adenocarcinoma [10], and colorectal cancer [11]. This potential of UQCRB to cause disease indicates its important role in angiogenesis and other mitochondria-mediated disorders.
In a recent report on the hereditary defects of the UQCRB gene, a Turkish girl with UQCRB and isolated complex III defects showed hypoglycemia and lactic acidosis during a metabolic crisis in her babyhood, but had normal growth in her childhood [2]. Based on this result, the present inventors constructed UQCRB mutant stable cell lines MT1 and MT2 and investigated their biological functions in angiogenesis. Notably, MT1 and MT2 showed remarkably increased growth and pro-angiogenic activities, together with mitochondrial structural abnormalities. Conversely, the cell proliferation of UQCRB mutants was significantly decreased by treatment with the UQCRB inhibitors terpestacin and A1938.
In summary, these results suggest that UQCRB and its mutation play a key role in angiogenesis and that UQCRB mutants could be useful tools for exploring the functions of UQCRB in human cells.
Throughout the entire specification, many papers and patent documents are referenced and their citations are represented. The disclosures of cited papers and patent documents are entirely incorporated by reference into the present specification, and the level of the technical field within which the present invention falls and details of the present invention are explained more clearly.